Lawn mower sharpening device



June 25, 1935. .M. MICHALSKI LAWN MOWER SHARPENING DEVICE Filed Aug. 10, 1932 HIS ATTORNEYS Patented June 25, 1935 PA-TENT OFFICE LAWN MOWER SHARPENING DEVICE Martin Michalski, North Chicago, 11!.

Application August 10, 1932, Serial No. 628,253

1 Claim.

This invention relates to certain novel improve ments in lawn mower sharpening devices, and has for its principal object the provision of an improved construction of this character which will be highly efficient in use and economical in manufacture.

It is an object of this invention to provide an improvement over the device shown in my Patent No. 1,843,830, dated February 2, 1932. In that patent there is shown a sharpening device which is yieldably engaged by the revolving blades of the lawn mower to bring about frictional engagement of the cutting edges of the blades with the abrasive surface of the sharpening device. In the patent referred to I arrange the abrasive surface on a stiff backing strip. I have discovered that this necessitated frequent removal of the backing strip and replacement of the abrasive thereon.

In the present invention I overcome this objectionable feature of the stiff backing strip in the patent by arranging the abrasive surface on a flexible sheet or web which is wound upon a feed roll from which the free end portion of the web may be fed out of a delivery slot to supply a fresh section of the abrasive web to the blades of the mower as the abrasive surface thereon is worn off in use.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawing, showing the preferred form of construction and in which:

Fig. 1 is a front elevation showing the invention applied to a conventional lawn mower;

Fig. 2 is a transverse vertical sectional view;

Fig. 3 is a perspective view showing the new abrasive feed roll, and its mounting;

Fig. 4 is a perspective view of the yieldable member which urges the abrasive against the blades of the mower;

Fig. 5 is a transverse vertical section through the feed roll and web shown in Fig. 3;

Fig. 6 is a sectional view on line 6--6 in Fig. 5; and

Fig. 7 is an end elevational view of the new feed roll.

50 In the drawing a conventional lawn mower is indicated generally at In and includes the revolving blades II and the usual brace rod l2 extending between the wheels l3. My new device is generally indicated at M and includes a supporting frame l5. This frame l5 includes a rear wall l8 and end walls l6 and I1 in which is journaled a feed roll l9. Arranged upon the feed roll I9 is a web 20 of flexible abrasive material which may be, for example, sand paper, emery paper or the like. The free end 20a of the web is fed out through a dispensing slot 2| formed in the rear wall [8 of the frame.

Means, in the form of hangers 22 carried by the frame l5, are provided for mounting the device on a mower and to accomplish this end these clips 22 are suspended from the rod l2 as shown in Figs. 1 and 2. The frame l5 and feed roll l9 are thus yieldablysuspended from the rod I2. Means are also provided for yieldably urging the free'end portion 20a of the web into the path of the revolvable blades H and to this end I mount on the rod l2 a yieldable member in the form of a flat spring 23. This spring exerts a bearing reaction on the web 20 and frame IE to urge the free end 20a. of the Web into the path of the blades H. Flat springs 24 are provided on the frame I5 to exert a braking action on the web 20.

On one end of the feed r011 I9 I mount a finger grip in the form of a wing nut 25 and on the other end of the feed roll I9 I mount a ratchet 26. One end of a resilient dog 21 is mounted on the rear wall l8 and this dog has a free end that bears on the ratchet 26 to prevent unwinding of the feed roll 19 and web 20.

After the abrasive surface is worn from the free end portion 26a of the abrasive web 20, the web 20 may be unwound and a fresh portion thereof delivered out of the dispensing slot 2| by releasing the dog 21 from the ratchet 26 and then rotating the web 28 and feed roll 19 clockwise (Fig. 5) by means of the finger grip 25. When the entire web 20 is used up a new roll of abrasive may be wound upon the feed roll H by loosening the yieldable member 23 on the rod I2, releasing the dog 21 from the ratchet 26, starting the web 20 around the roll l9, and then rotating the roll counterclockwise by means of the finger grip 25. Thus with this new device the inconvenience of removing the stiff backing strips of the prior art devices from the mower to replace the abrasive thereon is eliminated.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification, without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claim.

Having thus described my invention what I claim as new and desire to protect by Letters Patout is:

In a lawn mower comprising aframe structure, a brace bar carried thereby, and a bladed cutter mounted for rotation on the frame structure, a frame comprising a wall having a slot therethrough, two spaced flanges carried by said wall, a floor connected with the wall and said flanges, a roll of abrasive material mounted between said fianges, the web of said roll extending through the slot in said wall, the latter constituting a backing surface for the web projecting through the slot, hooks connected with said wall for connection with the brace bar, to hold the backing surface of said wall in operative relation with the bladed cutter, resilient means urging the wall in the direction of the bladed cutter, to support the abrasive lying against the backing surface in the path of the blades, and brake members carried by said floor for yieldingly resisting unwinding rotation of the roll of abrasive material.

MARTIN MICHALSKI. 

